The present invention relates to a system for stereotactic radiotherapy using a computerized tomographic scanning system as an on-line controller, and more particularly to a system for a stereotactic radiation therapy with a linear accelerator which is operated in accordance with information obtained by the computerized tomographic scanning system.
Referring to FIGS. 1 and 2 showing a conventional linear accelerator LA, a rotating frame 2 having an X-ray head 4 is rotatably mounted on a base 9 so as to be rotated about horizontal axis 1. The X-ray head 4 is provided such that an axis 3 of X-ray beams intersects the axis 1 at an isocenter 5. Consequently, reciprocative rotation of the rotating frame 2 causes the X-rays to always pass the isocenter 5, which means that the X-rays concentrate to the isocenter 5. Therefore, an affected part of a patient is effectively treated.
However, in the conventional system, since the X-rays reciprocate in the same plane, other healthy parts in the plane may be affected by the radiation.
On the other hand, the position of the lesion is determined by the eye-measurement of the operator in accordance with CT (Computed Tomography) scan data or data obtained by MRI (Magnetic Resonance Imaging) which were obtained at another place before the treatment. Therefore, the X-rays controlled by the eye-measurement not always are irradiated to the lesion.